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'Jean le Rond d'Alembert' (
November 16,
1717 –
October 29,
1783) was a
French mathematician,
mechanician,
physicist and
philosopher. He was also co-editor with
Denis Diderot of the ''
Encyclopédie''. D'Alembert's method for the
wave equation is named after him.
Childhood
Born in
Paris, d'Alembert was the illegitimate child of the writer
Claudine Guérin de Tencin and the chevalier
Louis-Camus Destouches, an
artillery officer. Destouches was abroad at the time of d'Alembert's birth, and a couple of days after birth his mother left him on the steps of the
Saint-Jean-le-Rond de Paris church. According to custom, he was named after the patron saint of the church. D'Alembert was placed in an
orphanage for found children, but was soon adopted by the wife of a glazier. Destouches secretly paid for the education of Jean le Rond, but did not want his parentage officially recognised.
Studies and Adult Life
D'Alembert first attended a private school. The chevalier Destouches left d'Alembert an
annuity of 1200
livres on his death in
1726. Under the influence of the Destouches family, at the age of twelve D'Alembert entered the
jansenist Collège des Quatre-Nations (the institution was also known under the name "Collège Mazarin"). Here he studied
philosophy,
law, and the
arts, graduating as ''
bachelier'' in
1735. In his later life, D'Alembert scorned the
Cartesian principles he had been taught by the Jansenists: "physical premotion, innate ideas and the vortices".
The Jansenists steered D'Alembert toward an ecclesiastical career, attempting to deter him from pursuits such as
poetry and
mathematics.
Theology was, however, "rather unsubstantial fodder" for d'Alembert. He entered law school for two years, and was nominated ''
avocat'' in
1738.
He was also interested in
medicine and mathematics. Jean was first registered under the name ''Daremberg'', but later changed it to ''d'Alembert''. In July of
1739 he made his first contribution to the field of mathematics, pointing out the errors he had detected in ''
L'analyse démontrée'' (published
1708 by
Charles René Reynaud) in a communication addressed to the
Académie des Sciences. At the time ''L'analyse démontrée'' was a standard work, which D'Alembert himself had used to study the foundations of mathematics. D'Alembert was also a Latin scholar of some note and worked in the latter part of his life on a superb translation of
Tacitus, from which he received wide praise including that of
Denis Diderot.
In
1740, he submitted his second
scientific work from the field of
fluid mechanics ''Memoire sur le refraction des corps solides'', which was recognized by
Clairaut. In this work d'Alembert theoretically explained
refraction. He also wrote about what is now called
D'Alembert's paradox: that the
drag on a body immersed in an
inviscid,
incompressible fluid is zero.
D'Alembert was a participant in several Parisian
salons, particularly those of
Madame Geoffrin, of the
marquise du Deffand and of
Mademoiselle de Lespinasse. There he met
Denis Diderot.
When the ''Encyclopédie'' was organized in the late 1740s, d'Alembert was engaged as co-editor (for mathematics and science) with Diderot, and served until a series of crises temporarily interrupted the publication in 1757. He authored over a thousand articles for it, including the famous ''
Preliminary Discourse''.
Aged 23, he entered the Académie des sciences, and joined the
Académie de Berlin at 28. In
1754, d'Alembert was elected a member of the
Académie française, of which he became Permanent Secretary on
9 April 1772.
While he made great strides in mathematics and physics, d'Alembert is also famously known for incorrectly arguing in ''Croix ou Pile'' that the
probability of a coin landing heads increased for every time that it came up tails. In
gambling, the strategy of decreasing one's bet the more one wins and increasing one's bet the more one loses is therefore called ''the
D'Alembert system'', a type of
martingale.
He suffered bad health for many years and his death was as the result of a bladder illness. As a known unbeliever, D'Alembert was buried in a common unmarked grave.
In
France, the
fundamental theorem of algebra is known as the d'Alembert/
Gauss theorem.
He also created his
ratio test, a test to see if a
series converges.
He lived in an apartment with
Julie de Lespinasse, a famous Parisian salonnière with whom he was infatuated.
Bibliography
★ Grimsley, Ronald. (1963). ''Jean d'Alembert.'' Oxford: Clarenden Press.
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See also
★
Liberalism
★
Contributions to liberal theory
★
Gambler's fallacy
★
Wave equation
★
D'Alembert's principle
★
Preliminary Discourse to the Encyclopedia of Diderot
External links
★
D'Alembert's accusation of Euler's plagiarism at
Convergence
★
English translation of part of the Encyclopédie of Diderot and d'Alembert
★